[PATCH 0/3] firewire: small refactoring

[PATCH 0/3] firewire: small refactoring

[Stefan Richter]

This moves some functionality related to config ROM parsing into a core
function for use by drivers (repost of a patch from Clemens Ladisch to
linux1394-devel), plus small related bits.

firewire: add fw_csr_string() helper function
firewire: core: fw_csr_string addendum
firewire: qualify config ROM cache pointers as const pointers

 drivers/firewire/core-device.c          |  127 ++++++++++++++++--------
 drivers/firewire/sbp2.c                 |    5 
 drivers/media/dvb/firewire/firedtv-fw.c |   39 -------
 include/linux/firewire.h                |   11 +-
 4 files changed, 103 insertions(+), 79 deletions(-)
-- 
Stefan Richter
-=====-==--= ==-- ==-=-
http://arcgraph.de/sr/

[PATCH 1/3 resend] firewire: add fw_csr_string() helper function

[Stefan Richter]

Date: Thu, 24 Dec 2009 11:59:57 +0100
From: Clemens Ladisch <clemens@ladisch.de>

The core (sysfs attributes), the firedtv driver, and possible future
drivers all read strings from some configuration ROM directory.  Factor
out the generic code from show_text_leaf() into a new helper function,
modified slightly to handle arbitrary buffer sizes.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/core-device.c          |  110 +++++++++++++++++-------
 drivers/media/dvb/firewire/firedtv-fw.c |   39 +--------
 include/linux/firewire.h                |    2 +
 3 files changed, 84 insertions(+), 67 deletions(-)

Index: linux-2.6.33-rc2/include/linux/firewire.h
===================================================================
--- linux-2.6.33-rc2.orig/include/linux/firewire.h
+++ linux-2.6.33-rc2/include/linux/firewire.h
@@ -72,6 +72,8 @@ struct fw_csr_iterator {
 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 *p);
 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value);
 
+int fw_csr_string(u32 *directory, int key, char *buf, size_t size);
+
 extern struct bus_type fw_bus_type;
 
 struct fw_card_driver;
Index: linux-2.6.33-rc2/drivers/firewire/core-device.c
===================================================================
--- linux-2.6.33-rc2.orig/drivers/firewire/core-device.c
+++ linux-2.6.33-rc2/drivers/firewire/core-device.c
@@ -59,6 +59,67 @@ int fw_csr_iterator_next(struct fw_csr_i
 }
 EXPORT_SYMBOL(fw_csr_iterator_next);
 
+static u32 *search_leaf(u32 *directory, int search_key)
+{
+	struct fw_csr_iterator ci;
+	int last_key = 0, key, value;
+
+	fw_csr_iterator_init(&ci, directory);
+	while (fw_csr_iterator_next(&ci, &key, &value)) {
+		if (last_key == search_key &&
+		    key == (CSR_DESCRIPTOR | CSR_LEAF))
+			return ci.p - 1 + value;
+		last_key = key;
+	}
+	return NULL;
+}
+
+static int textual_leaf_to_string(u32 *block, char *buf, size_t size)
+{
+	unsigned int quadlets, length;
+
+	if (!size || !buf)
+		return -EINVAL;
+
+	quadlets = min(block[0] >> 16, 256u);
+	if (quadlets < 2)
+		return -ENODATA;
+
+	if (block[1] != 0 || block[2] != 0)
+		/* unknown language/character set */
+		return -ENODATA;
+
+	block += 3;
+	quadlets -= 2;
+	for (length = 0; length < quadlets * 4 && length + 1 < size; length++) {
+		char c = block[length / 4] >> (24 - 8 * (length % 4));
+		if (c == '\0')
+			break;
+		buf[length] = c;
+	}
+	buf[length] = '\0';
+	return length;
+}
+
+/**
+ * fw_csr_string - reads a string from the configuration ROM
+ * @directory: device or unit directory;
+ *             fw_device->config_rom+5 or fw_unit->directory
+ * @key: the key of the preceding directory entry
+ * @buf: where to put the string
+ * @size: size of @buf, in bytes
+ *
+ * Returns string length (>= 0) or error code (< 0).
+ */
+int fw_csr_string(u32 *directory, int key, char *buf, size_t size)
+{
+	u32 *leaf = search_leaf(directory, key);
+	if (!leaf)
+		return -ENOENT;
+	return textual_leaf_to_string(leaf, buf, size);
+}
+EXPORT_SYMBOL(fw_csr_string);
+
 static bool is_fw_unit(struct device *dev);
 
 static int match_unit_directory(u32 *directory, u32 match_flags,
@@ -226,10 +287,10 @@ static ssize_t show_text_leaf(struct dev
 {
 	struct config_rom_attribute *attr =
 		container_of(dattr, struct config_rom_attribute, attr);
-	struct fw_csr_iterator ci;
-	u32 *dir, *block = NULL, *p, *end;
-	int length, key, value, last_key = 0, ret = -ENOENT;
-	char *b;
+	u32 *dir;
+	size_t bufsize;
+	char dummy_buf[2];
+	int ret;
 
 	down_read(&fw_device_rwsem);
 
@@ -238,40 +299,23 @@ static ssize_t show_text_leaf(struct dev
 	else
 		dir = fw_device(dev)->config_rom + 5;
 
-	fw_csr_iterator_init(&ci, dir);
-	while (fw_csr_iterator_next(&ci, &key, &value)) {
-		if (attr->key == last_key &&
-		    key == (CSR_DESCRIPTOR | CSR_LEAF))
-			block = ci.p - 1 + value;
-		last_key = key;
+	if (buf) {
+		bufsize = PAGE_SIZE - 1;
+	} else {
+		buf = dummy_buf;
+		bufsize = 1;
 	}
 
-	if (block == NULL)
-		goto out;
-
-	length = min(block[0] >> 16, 256U);
-	if (length < 3)
-		goto out;
-
-	if (block[1] != 0 || block[2] != 0)
-		/* Unknown encoding. */
-		goto out;
+	ret = fw_csr_string(dir, attr->key, buf, bufsize);
 
-	if (buf == NULL) {
-		ret = length * 4;
-		goto out;
+	if (ret >= 0) {
+		/* Strip trailing whitespace and add newline. */
+		while (ret > 0 && isspace(buf[ret - 1]))
+			ret--;
+		strcpy(buf + ret, "\n");
+		ret++;
 	}
 
-	b = buf;
-	end = &block[length + 1];
-	for (p = &block[3]; p < end; p++, b += 4)
-		* (u32 *) b = (__force u32) __cpu_to_be32(*p);
-
-	/* Strip trailing whitespace and add newline. */
-	while (b--, (isspace(*b) || *b == '\0') && b > buf);
-	strcpy(b + 1, "\n");
-	ret = b + 2 - buf;
- out:
 	up_read(&fw_device_rwsem);
 
 	return ret;
Index: linux-2.6.33-rc2/drivers/media/dvb/firewire/firedtv-fw.c
===================================================================
--- linux-2.6.33-rc2.orig/drivers/media/dvb/firewire/firedtv-fw.c
+++ linux-2.6.33-rc2/drivers/media/dvb/firewire/firedtv-fw.c
@@ -239,47 +239,18 @@ static const struct fw_address_region fc
 };
 
 /* Adjust the template string if models with longer names appear. */
-#define MAX_MODEL_NAME_LEN ((int)DIV_ROUND_UP(sizeof("FireDTV ????"), 4))
-
-static size_t model_name(u32 *directory, __be32 *buffer)
-{
-	struct fw_csr_iterator ci;
-	int i, length, key, value, last_key = 0;
-	u32 *block = NULL;
-
-	fw_csr_iterator_init(&ci, directory);
-	while (fw_csr_iterator_next(&ci, &key, &value)) {
-		if (last_key == CSR_MODEL &&
-		    key == (CSR_DESCRIPTOR | CSR_LEAF))
-			block = ci.p - 1 + value;
-		last_key = key;
-	}
-
-	if (block == NULL)
-		return 0;
-
-	length = min((int)(block[0] >> 16) - 2, MAX_MODEL_NAME_LEN);
-	if (length <= 0)
-		return 0;
-
-	/* fast-forward to text string */
-	block += 3;
-
-	for (i = 0; i < length; i++)
-		buffer[i] = cpu_to_be32(block[i]);
-
-	return length * 4;
-}
+#define MAX_MODEL_NAME_LEN sizeof("FireDTV ????")
 
 static int node_probe(struct device *dev)
 {
 	struct firedtv *fdtv;
-	__be32 name[MAX_MODEL_NAME_LEN];
+	char name[MAX_MODEL_NAME_LEN];
 	int name_len, err;
 
-	name_len = model_name(fw_unit(dev)->directory, name);
+	name_len = fw_csr_string(fw_unit(dev)->directory, CSR_MODEL,
+				 name, sizeof(name));
 
-	fdtv = fdtv_alloc(dev, &backend, (char *)name, name_len);
+	fdtv = fdtv_alloc(dev, &backend, name, name_len >= 0 ? name_len : 0);
 	if (!fdtv)
 		return -ENOMEM;
 

-- 
Stefan Richter
-=====-==--= ==-- ==-=-
http://arcgraph.de/sr/

[PATCH 2/3] firewire: core: fw_csr_string addendum

[Stefan Richter]

Witespace and comment changes, and a different way to say i + 1 < end.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/core-device.c |   26 ++++++++++++++++----------
 include/linux/firewire.h       |    1 -
 2 files changed, 16 insertions(+), 11 deletions(-)

Index: linux-2.6.33-rc2/drivers/firewire/core-device.c
===================================================================
--- linux-2.6.33-rc2.orig/drivers/firewire/core-device.c
+++ linux-2.6.33-rc2/drivers/firewire/core-device.c
@@ -69,19 +69,22 @@ static u32 *search_leaf(u32 *directory, 
 		if (last_key == search_key &&
 		    key == (CSR_DESCRIPTOR | CSR_LEAF))
 			return ci.p - 1 + value;
+
 		last_key = key;
 	}
+
 	return NULL;
 }
 
 static int textual_leaf_to_string(u32 *block, char *buf, size_t size)
 {
-	unsigned int quadlets, length;
+	unsigned int quadlets, i;
+	char c;
 
 	if (!size || !buf)
 		return -EINVAL;
 
-	quadlets = min(block[0] >> 16, 256u);
+	quadlets = min(block[0] >> 16, 256U);
 	if (quadlets < 2)
 		return -ENODATA;
 
@@ -91,31 +94,34 @@ static int textual_leaf_to_string(u32 *b
 
 	block += 3;
 	quadlets -= 2;
-	for (length = 0; length < quadlets * 4 && length + 1 < size; length++) {
-		char c = block[length / 4] >> (24 - 8 * (length % 4));
+	for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
+		c = block[i / 4] >> (24 - 8 * (i % 4));
 		if (c == '\0')
 			break;
-		buf[length] = c;
+		buf[i] = c;
 	}
-	buf[length] = '\0';
-	return length;
+	buf[i] = '\0';
+
+	return i;
 }
 
 /**
  * fw_csr_string - reads a string from the configuration ROM
- * @directory: device or unit directory;
- *             fw_device->config_rom+5 or fw_unit->directory
+ * @directory: e.g. root directory or unit directory
  * @key: the key of the preceding directory entry
  * @buf: where to put the string
  * @size: size of @buf, in bytes
  *
- * Returns string length (>= 0) or error code (< 0).
+ * The string is taken from a minimal ASCII text descriptor leaf after
+ * the immediate entry with @key.  The string is zero-terminated.
+ * Returns strlen(buf) or a negative error code.
  */
 int fw_csr_string(u32 *directory, int key, char *buf, size_t size)
 {
 	u32 *leaf = search_leaf(directory, key);
 	if (!leaf)
 		return -ENOENT;
+
 	return textual_leaf_to_string(leaf, buf, size);
 }
 EXPORT_SYMBOL(fw_csr_string);
Index: linux-2.6.33-rc2/include/linux/firewire.h
===================================================================
--- linux-2.6.33-rc2.orig/include/linux/firewire.h
+++ linux-2.6.33-rc2/include/linux/firewire.h
@@ -71,7 +71,6 @@ struct fw_csr_iterator {
 
 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 *p);
 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value);
-
 int fw_csr_string(u32 *directory, int key, char *buf, size_t size);
 
 extern struct bus_type fw_bus_type;

-- 
Stefan Richter
-=====-==--= ==-- ==-=-
http://arcgraph.de/sr/

[PATCH 3/3] firewire: qualify config ROM cache pointers as const pointers

[Stefan Richter]

Several config ROM related functions only peek at the ROM cache; mark
their arguments as const pointers.  Ditto fw_device.config_rom and
fw_unit.directory, as the memory behind them is meant to be write-once.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/firewire/core-device.c |   21 +++++++++++----------
 drivers/firewire/sbp2.c        |    5 +++--
 include/linux/firewire.h       |   12 ++++++------
 3 files changed, 20 insertions(+), 18 deletions(-)

Index: linux-2.6.33-rc2/drivers/firewire/core-device.c
===================================================================
--- linux-2.6.33-rc2.orig/drivers/firewire/core-device.c
+++ linux-2.6.33-rc2/drivers/firewire/core-device.c
@@ -43,7 +43,7 @@
 
 #include "core.h"
 
-void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
+void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
 {
 	ci->p = p + 1;
 	ci->end = ci->p + (p[0] >> 16);
@@ -59,7 +59,7 @@ int fw_csr_iterator_next(struct fw_csr_i
 }
 EXPORT_SYMBOL(fw_csr_iterator_next);
 
-static u32 *search_leaf(u32 *directory, int search_key)
+static const u32 *search_leaf(const u32 *directory, int search_key)
 {
 	struct fw_csr_iterator ci;
 	int last_key = 0, key, value;
@@ -76,7 +76,7 @@ static u32 *search_leaf(u32 *directory, 
 	return NULL;
 }
 
-static int textual_leaf_to_string(u32 *block, char *buf, size_t size)
+static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
 {
 	unsigned int quadlets, i;
 	char c;
@@ -116,9 +116,9 @@ static int textual_leaf_to_string(u32 *b
  * the immediate entry with @key.  The string is zero-terminated.
  * Returns strlen(buf) or a negative error code.
  */
-int fw_csr_string(u32 *directory, int key, char *buf, size_t size)
+int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
 {
-	u32 *leaf = search_leaf(directory, key);
+	const u32 *leaf = search_leaf(directory, key);
 	if (!leaf)
 		return -ENOENT;
 
@@ -128,7 +128,7 @@ EXPORT_SYMBOL(fw_csr_string);
 
 static bool is_fw_unit(struct device *dev);
 
-static int match_unit_directory(u32 *directory, u32 match_flags,
+static int match_unit_directory(const u32 *directory, u32 match_flags,
 				const struct ieee1394_device_id *id)
 {
 	struct fw_csr_iterator ci;
@@ -262,7 +262,7 @@ static ssize_t show_immediate(struct dev
 	struct config_rom_attribute *attr =
 		container_of(dattr, struct config_rom_attribute, attr);
 	struct fw_csr_iterator ci;
-	u32 *dir;
+	const u32 *dir;
 	int key, value, ret = -ENOENT;
 
 	down_read(&fw_device_rwsem);
@@ -293,7 +293,7 @@ static ssize_t show_text_leaf(struct dev
 {
 	struct config_rom_attribute *attr =
 		container_of(dattr, struct config_rom_attribute, attr);
-	u32 *dir;
+	const u32 *dir;
 	size_t bufsize;
 	char dummy_buf[2];
 	int ret;
@@ -421,7 +421,7 @@ static ssize_t guid_show(struct device *
 	return ret;
 }
 
-static int units_sprintf(char *buf, u32 *directory)
+static int units_sprintf(char *buf, const u32 *directory)
 {
 	struct fw_csr_iterator ci;
 	int key, value;
@@ -503,7 +503,8 @@ static int read_rom(struct fw_device *de
  */
 static int read_bus_info_block(struct fw_device *device, int generation)
 {
-	u32 *rom, *stack, *old_rom, *new_rom;
+	const u32 *old_rom, *new_rom;
+	u32 *rom, *stack;
 	u32 sp, key;
 	int i, end, length, ret = -1;
 
Index: linux-2.6.33-rc2/drivers/firewire/sbp2.c
===================================================================
--- linux-2.6.33-rc2.orig/drivers/firewire/sbp2.c
+++ linux-2.6.33-rc2/drivers/firewire/sbp2.c
@@ -1014,7 +1014,8 @@ static int sbp2_add_logical_unit(struct 
 	return 0;
 }
 
-static int sbp2_scan_logical_unit_dir(struct sbp2_target *tgt, u32 *directory)
+static int sbp2_scan_logical_unit_dir(struct sbp2_target *tgt,
+				      const u32 *directory)
 {
 	struct fw_csr_iterator ci;
 	int key, value;
@@ -1027,7 +1028,7 @@ static int sbp2_scan_logical_unit_dir(st
 	return 0;
 }
 
-static int sbp2_scan_unit_dir(struct sbp2_target *tgt, u32 *directory,
+static int sbp2_scan_unit_dir(struct sbp2_target *tgt, const u32 *directory,
 			      u32 *model, u32 *firmware_revision)
 {
 	struct fw_csr_iterator ci;
Index: linux-2.6.33-rc2/include/linux/firewire.h
===================================================================
--- linux-2.6.33-rc2.orig/include/linux/firewire.h
+++ linux-2.6.33-rc2/include/linux/firewire.h
@@ -65,13 +65,13 @@
 #define CSR_DIRECTORY_ID	0x20
 
 struct fw_csr_iterator {
-	u32 *p;
-	u32 *end;
+	const u32 *p;
+	const u32 *end;
 };
 
-void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 *p);
+void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p);
 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value);
-int fw_csr_string(u32 *directory, int key, char *buf, size_t size);
+int fw_csr_string(const u32 *directory, int key, char *buf, size_t size);
 
 extern struct bus_type fw_bus_type;
 
@@ -163,7 +163,7 @@ struct fw_device {
 	struct mutex client_list_mutex;
 	struct list_head client_list;
 
-	u32 *config_rom;
+	const u32 *config_rom;
 	size_t config_rom_length;
 	int config_rom_retries;
 	unsigned is_local:1;
@@ -205,7 +205,7 @@ int fw_device_enable_phys_dma(struct fw_
  */
 struct fw_unit {
 	struct device device;
-	u32 *directory;
+	const u32 *directory;
 	struct fw_attribute_group attribute_group;
 };
 

-- 
Stefan Richter
-=====-==--= ==-- ==-=-
http://arcgraph.de/sr/